Grade:

$6$

A crane is used to lower weights into the sea $($density $=1025k\frac{g}{m}3)$ for an underwater construction project $($see Figure$).$ Determine the tension in the rope of the crane due to a rectangular concrete block $1m1m2\mathrm{.}0m($concrete density $=2300k\frac{g}{m}3)$ when it is:

$($a$)$ Suspended in the air and

$($b$)$ Completely immersed in water.